Prediabetes in Older Adults: Who Will Get Diabetes?

Body weight, systolic blood pressure, and cardiovascular disease are key factors, study found

Of 981 adults ages 60 or older with prediabetes who were followed for 12 years, 204 (22%) reverted to normoglycemia and 119 (13%) developed diabetes, reported researchers led by Ying Shang, a graduate student at the Karolinska Institutet in Stockholm.

A total of 23% of patients died during the study, and the remaining 42% maintained stable blood sugar levels. "During a 12-year follow-up, most of the older adults with prediabetes remained stable or reverted to normoglycemia, whereas only one-third developed diabetes or died," the team wrote online in the Journal of Internal Medicine.

"Although the progression of prediabetes is often described in working-age adults, the evidence on the progression, reversion, and mortality of prediabetes in older adults is limited. Given the high prevalence and heterogeneous outcomes of prediabetes in old age, it is pivotal to investigate the natural course of prediabetes amongst older adults," the researchers said.

Systolic blood pressure, heart diseases, and weight loss were associated with reverting to normal blood sugar levels in older adults. Normoglycemia was inversely associated with higher systolic blood pressure (OR = 0.9, 95% CI 0.8–0.9) and heart disease (OR = 0.5, 95% CI 0.3–0.9), while it had a direct relationship with weight loss (OR = 2.0, 95% CI 1.1–3.2).

Obesity was strongly linked with disease progression. Older adults with prediabetes who were obese at baseline were nearly three times more likely to develop diabetes compared with those of normal weight (OR=2.8, 95% CI 1.3-6.6), the study found.

The results suggest that even in old age, reverting from prediabetes to normal blood sugar levels can be achieved with effective weight management and blood pressure control, Shang and colleagues said. "Weight management may be an effective strategy for preventing prediabetes and its progression to diabetes, possibly by improving insulin sensitivity. For example, weight loss, which can be achieved through regular physical activity, could be recommended to older adults with overweight or obesity, as a possible effective strategy to restore normoglycemia."

Current guidelines emphasize lowering systolic blood pressure to improve glycemic control in diabetes, the team noted. "Based on this, we believe that even at the prediabetic stage, lowering the systolic blood pressure levels might improve glycaemia, thus promoting normoglycemia restoration. However, reduction of blood pressure should not be excessively strict in very old people in order to avoid, for example, possible falls due to hypotension."

Study Details

The study included diabetes-free participants ages 60 or older from the Swedish National Study on Aging and Care in Kungsholmen. More than half (65%) were women, and the mean age was 74. Data on demographic and lifestyle factors, current medication use, and medical history were collected through structured interviews and clinical examinations conducted by trained nurses and physicians. These were carried out at baseline, and then every 3 years for participants ages 78 and older and every 6 years for the rest.

Diabetes was defined as a glycated hemoglobin (HbA1c) level of 6.5% or higher. Prediabetes was defined as an HbA1c of 5.7% to 6.4%. Normoglycemia was defined as less than 5.7%. Weight loss was defined as a body weight reduction of 5 kg or more. The researchers used a multinomial logistic regression analysis to calculate odds ratios and 95% confidence intervals of factors associated with reversion to normoglycemia and progression to diabetes.

Study limitations, Shang and colleagues noted, were that there was no differentiation among diabetes phenotypes associated with impaired glucose tolerance, impaired fasting glucose, or the combination of the two. These "represent multiple pathophysiological abnormalities, which are likely to differ in their rates of evolution and clinical relevance," the team explained. "Moreover, the recommended HbA1c cutoffs to identify diabetes (≥6.5%) might have lower sensitivity compared to the oral glucose tolerance test. Therefore, the number of people with diabetes and the magnitude of observed associations may have been underestimated."

"We found that baseline body-mass index, weight changes, systolic blood pressure, and preexisting heart diseases could influence the natural history of prediabetes," the researchers continued. "The latter finding may help to identify people at high risk of progressing to diabetes and suggests possible strategies for achieving normoglycemia in older adults with prediabetes."

The study was supported by the Swedish Ministry of Health, the Swedish Research Council, the National Natural Science Foundation of China, and other organizations.

Shang and co-authors reported having no conflicts of interest

www red DiabetologNytt